CVE-2026-106433: Improper state management in MongoDB libmongocrypt can cause provider-specific data to be treated as an incomp

Routine

HIGH 8.8UPGRADE

CVE-2026-106433 is a high-severity flaw (CVSS 8.8) affecting libmongocrypt. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Improper state management in MongoDB libmongocrypt can cause provider-specific data to be treated as an incompatible type when cleaning up a key document containing duplicate masterKey fields. An authenticated actor who can modify key vault documents, or a server that returns such a key document, can cause invalid memory access and invalid frees in the client process. This can terminate the application or corrupt process memory.

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.3% (top 81%)
CISA exploited list	No
Weakness	CWE-843
Published	2026-10-08
Last modified	2026-10-27

Publisher (CNA): MongoDB, Inc. · Vendor: mongodb

Last updated 2026-10-27 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-10-08 19:16 UTCPublished CVE record published
2026-10-27 20:17 UTCUpdated Record last modified

mongodb libmongocrypt UPGRADE

Affected: >= 1.5.0 and < 1.20.5

Fixed in: 1.20.5

Safe to downgrade to: a release before 1.5.0

1. Check installed version

apt-cache policy libmongocrypt || rpm -q libmongocrypt || libmongocrypt --version

2. UPGRADE to 1.20.5 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade libmongocrypt

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade libmongocrypt

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 1.5.0 (Debian / Ubuntu)

apt-cache madison libmongocrypt sudo apt install libmongocrypt=<VERSION_BEFORE_1.5.0> sudo apt-mark hold libmongocrypt

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list libmongocrypt sudo dnf downgrade libmongocrypt-<VERSION_BEFORE_1.5.0> sudo dnf versionlock add libmongocrypt

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-106433?

libmongocrypt: upgrade to 1.20.5. Exact commands for each OS are on this page.

Is CVE-2026-106433 being exploited?

CVE-2026-106433 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-106433 affect?

CVE-2026-106433 affects libmongocrypt. Severity is high (CVSS 8.8). Improper state management in MongoDB libmongocrypt can cause provider-specific data to be treated as an incompatible type when cleaning up a key document containing duplicate masterKey fields. An authenticated actor who can modify key vault

How urgent is CVE-2026-106433?

Priority 35/100. High severity

Software pages

MongoDB vulnerabilities · HashiCorp Vault vulnerabilities

Related CVEs

CVE-2026-84962 MEDIUM 4.2 UPGRADE An unauthorized user with key vault write access may cause an authorized client to issue arbitrary authenticat
CVE-2026-81523 MEDIUM 4.4 UPGRADE A missing input-validation issue in MongoDB libmongocrypt's automatic-encryption context setup allows a caller
CVE-2026-84971 MEDIUM 6.5 UPGRADE Improper handling of an unexpected value size in the decryption path of a client-side encryption library can c

References

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